Heard some awesome tone from the 82', 83' shows yesterday. It would be nice to know if that was just another modded fender reverb or a mesa if that makes any sense. lol Anyone know when jerry was using them?

Mk I starting early in 1975 w/ the March S.N.A.C.K. show ( I figure it probable it appeared earlier w/ Legion of Mary, maybe even November-December '74? ), thru Detroit 10/3/76, the next shows being Oakland on the Green w/ the debut of the dual Twin unit.

Mk I also appears in undated (but 1979) Reconstruction photo on the jerrysite.com

The awesome tone from '82-'83 is definitely coming from the silverface Fender Twin Reverb into the McIntosh (maybe MC2500 during those years) and the vertical 4x12" stack of JBLs. That tone really is awesome in my opinion. I was just listening to an excellent audience of 5/13/83 and Jerry's tone is amazing. I kinda doubt the Mac clipping theory using the MC2500.